-*- mode: org -*-
#+TITLE:       sisudoc spine (doc_reform) output pod source abstraction peg text
#+DESCRIPTION: documents - structuring, publishing in multiple formats & search
#+FILETAGS:    :spine:output:source:pod:
#+AUTHOR:      Ralph Amissah
#+EMAIL:       [[mailto:ralph.amissah@gmail.com][ralph.amissah@gmail.com]]
#+COPYRIGHT:   Copyright (C) 2015 (continuously updated, current 2026) Ralph Amissah
#+LANGUAGE:    en
#+STARTUP:     content hideblocks hidestars noindent entitiespretty
#+PROPERTY:    header-args+ :eval never-export :exports code
#+PROPERTY:    header-args+ :noweb yes :padline no
#+PROPERTY:    header-args+ :results silent :cache no
#+PROPERTY:    header-args+ :mkdirp yes
#+OPTIONS:     H:3 num:nil toc:t \n:t ::t |:t ^:nil -:t f:t *:t
- magic single double-quote → " ← FIX changes hilighting behavior (occuring
  after it) in org document. INVESTIGATE (org-mode CONFIG?) FIND & FIX

- [[./doc-reform.org][doc-reform.org]]  [[./][org/]]

* (Object-Centric) Document Abstraction PEG text

- Process markup document, create document abstraction

** _module template_ :module:metadoc_from_src:

rename source_abstraction_peg_txt.d

#+HEADER: :tangle "../src/sisudoc/ocda/abstraction/ssp.d"
#+HEADER: :noweb yes
#+BEGIN_SRC d
<<doc_header_including_copyright_and_license>>
module sisudoc.ocda.abstraction.ssp;
@safe:
/+ ↓ write document abstraction as human-readable .ssp text file +/
/+ ↓ the format version, carried by both serialisations: the .ssp says it in
     its "% SiSU Document Abstraction v" header line and the .ocda.db in its
     metadata schema.version row, so that one bump moves both.

     a reader checks the major part and refuses what it does not know, rather
     than loading an older artefact half populated in silence. bump the minor
     part when a property is added (a reader of the newer format still reads
     the older one), the major part when one changes meaning or goes away.

     1.1  2026-09-10  @source block; the document metadata the output writers
                      read carried in full (14 meta and 3 make properties
                      added); .segment_lv4_is, the segment a cross
                      reference to a heading above level 4 lands on;
                      was 0.1
+/
enum ssp_format_version       = "<<ocda_ssp_format_version>>";
enum ssp_format_version_major = "<<ocda_ssp_format_version_part_major>>";
/+ ↓ escaping for values that are folded onto one line

     a .ssp property value runs to the end of its line, and
     .heading_ancestors_text joins its eight slots with "|", so a slot that
     itself contains "|", a backslash or a line break has to be escaped or
     the value cannot be read back. the pair here is the whole of the rule,
     used by the writer and by the reader.
+/
template sspEscape() {
  import std.array : replace;
  string sspEscapeValue(string _s) {
    return _s
      .replace("\\", "\\\\")
      .replace("|",  "\\|")
      .replace("\n", "\\n")
      .replace("\r", "\\r");
  }
  string[] sspUnescapeSplit(string _s) {
    string[] _out;
    string   _cur;
    bool     _esc;
    foreach (c; _s) {
      if (_esc) {
        switch (c) {
        case 'n': _cur ~= '\n'; break;
        case 'r': _cur ~= '\r'; break;
        default:  _cur ~= c;    break; // covers \\ and \|
        }
        _esc = false;
      } else if (c == '\\') {
        _esc = true;
      } else if (c == '|') {
        _out ~= _cur;
        _cur  = "";
      } else {
        _cur ~= c;
      }
    }
    _out ~= _cur;
    return _out;
  }
}
/+ ↓ one object record: the single definition of what an object looks
     like in a .ssp file. the writer emits with it, and the reader is
     checked against it by round trip, so the two cannot drift
+/
template sspObjectRecord() {
  import std.conv : to;
  import std.digest : toHexString;
  import std.stdio;
  import std.string;
  import std.array;
  import sisudoc.ocda.io_in.paths_source;
  mixin sspEscape;
  string[] sspObjectRecord(O)(O obj, string section, bool _vox = false) {
    string[] output;
    /+ ↓ object declaration line. a heading carries its identifier here,
         on the declaration line, where it is not the ocn; every other
         object carries it as .identifier below, on the same condition
    +/
    string obj_decl = "[" ~ obj.metainfo.ocn.to!string ~ "] ";
    if (obj.metainfo.is_a == "heading") {
      string lev = obj.metainfo.marked_up_level;
      obj_decl ~= "heading :" ~ lev;
      if (obj.metainfo.identifier.length > 0
        && obj.metainfo.identifier != obj.metainfo.ocn.to!string) {
        obj_decl ~= " " ~ obj.metainfo.identifier;
      }
    } else {
      obj_decl ~= obj.metainfo.is_a;
    }
    output ~= obj_decl;
    /+ ↓ properties (only non-default values) +/
    if (obj.metainfo.is_a != "heading"
      && obj.metainfo.identifier.length > 0
      && obj.metainfo.identifier != obj.metainfo.ocn.to!string) {
      output ~= ".identifier: " ~ obj.metainfo.identifier;
    }
    if (obj.metainfo.is_of_part.length > 0) {
      output ~= ".part: " ~ obj.metainfo.is_of_part;
    }
    if (obj.metainfo.is_of_section.length > 0
      && obj.metainfo.is_of_section != section) {
      output ~= ".section: " ~ obj.metainfo.is_of_section;
    }
    /+ ↓ parent: emitted for every object except:
         - the document root, the one object that has no parent
         - toc entries, generated furniture rather than authored objects,
           whose place is given by their indent level; the toc heading
           itself does carry its parent (the document root)
         A parent ocn of 0 is not "no parent recorded", it is a parent
         heading the author has made non-substantive (ocn suppressed, or a
         dummy heading introduced to segment an output); it is structurally
         truthful and is stated explicitly rather than omitted so that the
         two cases remain distinguishable in the file
    +/
    if (!(obj.metainfo.is_a == "heading"
      && obj.metainfo.heading_lev_markup == 0)
      && obj.metainfo.is_a != "toc"
    ) {
      output ~= ".parent: " ~ obj.metainfo.parent_ocn.to!string;
    }
    if (obj.metainfo.last_descendant_ocn != 0) {
      output ~= ".last_descendant: " ~ obj.metainfo.last_descendant_ocn.to!string;
    }
    /+ ↓ child headings (from pre-computed map) +/
    if (obj.metainfo.children_headings.length > 0) {
      string[] ch;
      foreach (c; obj.metainfo.children_headings) {
        ch ~= c.to!string;
      }
      output ~= ".children: " ~ ch.join(" ");
    }
    /+ ↓ ancestors (only if non-zero) +/
    {
      bool has_anc = false;
      foreach (a; obj.metainfo.markedup_ancestors) {
        if (a != 0) { has_anc = true; break; }
      }
      if (has_anc) {
        string anc;
        foreach (i, a; obj.metainfo.markedup_ancestors) {
          if (i > 0) { anc ~= " "; }
          anc ~= a.to!string;
        }
        output ~= ".ancestors: " ~ anc;
      }
    }
    /+ ↓ collapsed ancestors (only if non-zero) +/
    {
      bool has_anc_c = false;
      foreach (a; obj.metainfo.collapsed_ancestors) {
        if (a != 0) { has_anc_c = true; break; }
      }
      if (has_anc_c) {
        string anc;
        foreach (i, a; obj.metainfo.collapsed_ancestors) {
          if (i > 0) anc ~= " ";
          anc ~= a.to!string;
        }
        output ~= ".ancestors_collapsed: " ~ anc;
      }
    }
    /+ ↓ dom structure status (only if non-zero) +/
    {
      bool has_dom = false;
      foreach (d; obj.metainfo.dom_structure_markedup_tags_status) {
        if (d != 0) { has_dom = true; break; }
      }
      if (has_dom) {
        string ds;
        foreach (i, d; obj.metainfo.dom_structure_markedup_tags_status) {
          if (i > 0) { ds ~= " "; }
          ds ~= d.to!string;
        }
        output ~= ".dom_status: " ~ ds;
      }
    }
    {
      bool has_dom_c = false;
      foreach (d; obj.metainfo.dom_structure_collapsed_tags_status) {
        if (d != 0) { has_dom_c = true; break; }
      }
      if (has_dom_c) {
        string ds;
        foreach (i, d; obj.metainfo.dom_structure_collapsed_tags_status) {
          if (i > 0) { ds ~= " "; }
          ds ~= d.to!string;
        }
        output ~= ".dom_status_collapsed: " ~ ds;
      }
    }
    if (obj.metainfo.heading_lev_collapsed < 9) {
      output ~= ".heading_lev_collapsed: " ~ obj.metainfo.heading_lev_collapsed.to!string;
    }
    if (obj.metainfo.parent_lev_markup != 0) {
      output ~= ".parent_lev: " ~ obj.metainfo.parent_lev_markup.to!string;
    }
    if (obj.metainfo.dummy_heading) {
      output ~= ".dummy: true";
    }
    if (obj.metainfo.object_number_off) {
      output ~= ".ocn_off: true";
    }
    if (obj.metainfo.is_of_type.length > 0) {
      output ~= ".is_of_type: " ~ obj.metainfo.is_of_type;
    }
    if (obj.metainfo.attrib.length > 0) {
      output ~= ".attrib: " ~ obj.metainfo.attrib;
    }
    if (obj.metainfo.lang.length > 0) {
      output ~= ".meta_lang: " ~ obj.metainfo.lang;
    }
    if (obj.metainfo.syntax.length > 0) {
      output ~= ".meta_syntax: " ~ obj.metainfo.syntax;
    }
    /+ ↓ sha256 digest +/
    {
      bool has_sha = false;
      foreach (b; obj.metainfo.sha256.text) {
        if (b != 0) { has_sha = true; break; }
      }
      if (has_sha) {
        if (_vox) {
          writeln(obj.metainfo.sha256.summary);
        }
        output ~= ".sha256: " ~ obj.metainfo.sha256.text.toHexString.to!string;
      }
    }
    /+ ↓ images, repeatable record, one per image in order of appearance:
         .image: <filename> sha256:<HEX> bytes:<n> px:<width>x<height>
         .image: <filename> missing:true
       filename first (the object's handle on the image), remaining fields
       self-describing key:value tokens so that further fields can be
       added later without invalidating existing readers. px: is the
       file's own pixel size, not the display dimensions (w##h##) which
       the object text already carries
    +/
    if (obj.metainfo.sha256.images.length > 0) {
      foreach (i; obj.metainfo.sha256.images) {
        output ~= (i.fileMissing)
        ? ".image: "          ~ i.fileName
          ~ " missing:true"
        : ".image: "          ~ i.fileName
          ~ " sha256:"        ~ i.fileHash_sha256.toHexString.to!string
          ~ " bytes:"         ~ i.fileSize.to!string
          ~ ((i.imageWidth > 0 && i.imageHeight > 0)
            ? " px:"          ~ i.imageWidth.to!string
              ~ "x"           ~ i.imageHeight.to!string
            : "");
      }
    }
    /+ ↓ text attributes +/
    if (obj.attrib.indent_base != 0 || obj.attrib.indent_hang != 0) {
      output ~= ".indent: " ~ obj.attrib.indent_base.to!string
        ~ " " ~ obj.attrib.indent_hang.to!string;
    }
    if (obj.attrib.bullet) {
      output ~= ".bullet: true";
    }
    if (obj.attrib.language.length > 0) {
      output ~= ".lang: " ~ obj.attrib.language;
    }
    /+ ↓ has flags +/
    {
      string[] has_flags;
      if (obj.has.inline_links) { has_flags ~= "links"; }
      if (obj.has.inline_notes_reg) { has_flags ~= "notes_reg"; }
      if (obj.has.inline_notes_star) { has_flags ~= "notes_star"; }
      if (obj.has.images) { has_flags ~= "images"; }
      if (obj.has.image_without_dimensions) { has_flags ~= "images_no_dim"; }
      if (has_flags.length > 0) {
        output ~= ".has: " ~ has_flags.join(" ");
      }
    }
    /+ ↓ table properties +/
    if (obj.metainfo.is_a == "table" && obj.table.number_of_columns > 0) {
      output ~= ".table_cols: " ~ obj.table.number_of_columns.to!string;
      if (obj.table.column_widths.length > 0) {
        string[] ws;
        foreach (w; obj.table.column_widths) ws ~= w.to!string;
        output ~= ".table_widths: " ~ ws.join(" ");
      }
      if (obj.table.column_aligns.length > 0) {
        output ~= ".table_aligns: " ~ obj.table.column_aligns.join(" ");
      }
      if (obj.table.heading) {
        output ~= ".table_header: true";
      }
    }
    /+ ↓ code block properties +/
    if (obj.metainfo.is_a == "code") {
      if (obj.code_block.linenumbers) {
        output ~= ".code_linenumbers: true";
      }
    }
    /+ ↓ stow (extracted links) +/
    if (obj.stow.link.length > 0) {
      foreach (lnk; obj.stow.link) {
        if (lnk.length > 0) {
          output ~= ".stow_link: " ~ lnk;
        }
      }
    }
    /+ ↓ tag properties +/
    if (obj.tags.in_segment_html.length > 0) {
      output ~= ".segment: " ~ obj.tags.in_segment_html;
    }
    if (obj.tags.anchor_tag_html.length > 0
      && obj.tags.anchor_tag_html != obj.tags.in_segment_html) {
      output ~= ".anchor: " ~ obj.tags.anchor_tag_html;
    }
    if (obj.tags.segname_prev.length > 0) {
      output ~= ".segment_prev: " ~ obj.tags.segname_prev;
    }
    if (obj.tags.segname_next.length > 0) {
      output ~= ".segment_next: " ~ obj.tags.segname_next;
    }
    if (obj.tags.heading_lev_anchor_tag.length > 0) {
      output ~= ".heading_lev_anchor: " ~ obj.tags.heading_lev_anchor_tag;
    }
    if (obj.tags.segment_anchor_tag_epub.length > 0) {
      output ~= ".segment_epub: " ~ obj.tags.segment_anchor_tag_epub;
    }
    /+ ↓ the segment an object belongs to, as opposed to the segment a
         heading opens. .segment (in_segment_html) is set on headings
         only, so without these two a reader cannot tell which segment a
         paragraph is in; the sqlite search writer reads the html one
    +/
    if (obj.tags.html_segment_anchor_tag_is.length > 0) {
      output ~= ".segment_html_is: " ~ obj.tags.html_segment_anchor_tag_is;
    }
    if (obj.tags.epub_segment_anchor_tag_is.length > 0) {
      output ~= ".segment_epub_is: " ~ obj.tags.epub_segment_anchor_tag_is;
    }
    /+ ↓ the level 4 segment a cross reference to this heading lands on,
         emitted only where it is not the segment the heading sits in, which
         is every heading at level 4 or below +/
    if (obj.tags.segment_lv4_is.length > 0
      && obj.tags.segment_lv4_is != obj.tags.html_segment_anchor_tag_is
    ) {
      output ~= ".segment_lv4_is: " ~ obj.tags.segment_lv4_is;
    }
    /+ ↓ heading ancestors text +/
    {
      bool has_hat = false;
      foreach (h; obj.tags.heading_ancestors_text) {
        if (h.length > 0) { has_hat = true; break; }
      }
      if (has_hat) {
        string[] _hat;
        foreach (h; obj.tags.heading_ancestors_text) {
          _hat ~= sspEscapeValue(h.to!string);
        }
        output ~= ".heading_ancestors_text: " ~ _hat.join("|");
      }
    }
    /+ ↓ lev4 subtoc +/
    if (obj.tags.lev4_subtoc.length > 0) {
      foreach (st; obj.tags.lev4_subtoc) {
        if (st.length > 0) {
          output ~= ".lev4_subtoc: " ~ st;
        }
      }
    }
    /+ ↓ anchor tags +/
    if (obj.tags.anchor_tags.length > 0) {
      foreach (at; obj.tags.anchor_tags) {
        if (at.length > 0) {
          output ~= ".anchor_tag: " ~ at;
        }
      }
    }
    /+ ↓ text content +/
    if (obj.text.length > 0) {
      foreach (line; obj.text.split("\n")) {
        output ~= "| " ~ line;
      }
    }
    output ~= "";
    return output;
  }
}

/+ ↓ abstraction directories whose stale .ssp have been cleared this run, one
     entry per document. __gshared, and read and written only inside the
     synchronized block in the writer below: a document's languages share one
     abstraction directory and may be written in parallel
+/
private __gshared bool[string] _abstraction_dir_prepared;
template spineAbstractionTxt() {
  import std.conv : to;
  import std.digest : toHexString;
  import std.file;
  import std.path;
  import std.stdio;
  import std.string;
  import std.array;
  import sisudoc.ocda.io_in.paths_source;
  mixin sspObjectRecord;
  /+ ↓ the whole .ssp for a document, as lines. the file writer below emits
       these, and the abstraction db is built by reading them back, so the
       database cannot carry anything the .ssp does not
  +/
  string[] sspDocumentLines(D)(D doc) {
    auto doc_abstraction = doc.abstraction;
    auto doc_matters     = doc.matters;
    string[] output;
    /+ ↓ header comment +/
    output ~= "% SiSU Document Abstraction v" ~ ssp_format_version;
    output ~= "% Source: " ~ doc_matters.src.filename;
    output ~= "";
    /+ ↓ @source block: what this abstraction was made from, so a reader can
         say whether it is looking at the right images and whether the
         markup has moved on since. the filename is in the % Source: line
         above and is not repeated here
    +/
    output ~= "@source {";
    output ~= "  language: " ~ doc_matters.src.language;
    if (doc_matters.pod.manifest_list_of_languages.length > 0) {
      output ~= "  languages: " ~ doc_matters.pod.manifest_list_of_languages.join(" ");
    }
    output ~= "  digest: " ~ doc_matters.doc_digest.markup_doc.toHexString.to!string;
    output ~= "}";
    output ~= "";
    /+ ↓ @meta block +/
    output ~= "@meta {";
    auto meta = doc_matters.conf_make_meta.meta;
    if (meta.title_main.length > 0) {
      output ~= "  title.main: " ~ meta.title_main;
    }
    if (meta.title_subtitle.length > 0) {
      output ~= "  title.subtitle: " ~ meta.title_subtitle;
    }
    if (meta.title_full.length > 0) {
      output ~= "  title.full: " ~ meta.title_full;
    }
    if (meta.title_language.length > 0) {
      output ~= "  title.language: " ~ meta.title_language;
    }
    if (meta.title_edition.length > 0) {
      output ~= "  title.edition: " ~ meta.title_edition;
    }
    if (meta.creator_author.length > 0) {
      output ~= "  creator.author: " ~ meta.creator_author;
    }
    if (meta.creator_author_surname.length > 0) {
      output ~= "  creator.author_surname: " ~ meta.creator_author_surname;
    }
    if (meta.creator_author_surname_fn.length > 0) {
      output ~= "  creator.author_surname_fn: " ~ meta.creator_author_surname_fn;
    }
    if (meta.creator_author_email.length > 0) {
      output ~= "  creator.author_email: " ~ meta.creator_author_email;
    }
    if (meta.creator_illustrator.length > 0) {
      output ~= "  creator.illustrator: " ~ meta.creator_illustrator;
    }
    if (meta.creator_translator.length > 0) {
      output ~= "  creator.translator: " ~ meta.creator_translator;
    }
    if (meta.date_published.length > 0) {
      output ~= "  date.published: " ~ meta.date_published;
    }
    if (meta.date_created.length > 0) {
      output ~= "  date.created: " ~ meta.date_created;
    }
    if (meta.date_issued.length > 0) {
      output ~= "  date.issued: " ~ meta.date_issued;
    }
    if (meta.date_available.length > 0) {
      output ~= "  date.available: " ~ meta.date_available;
    }
    if (meta.date_modified.length > 0) {
      output ~= "  date.modified: " ~ meta.date_modified;
    }
    if (meta.date_valid.length > 0) {
      output ~= "  date.valid: " ~ meta.date_valid;
    }
    if (meta.date_added_to_site.length > 0) {
      output ~= "  date.added_to_site: " ~ meta.date_added_to_site;
    }
    if (meta.rights_copyright.length > 0) {
      output ~= "  rights.copyright: " ~ meta.rights_copyright;
    }
    if (meta.rights_copyright_text.length > 0) {
      output ~= "  rights.copyright_text: " ~ meta.rights_copyright_text;
    }
    if (meta.rights_copyright_translation.length > 0) {
      output ~= "  rights.copyright_translation: " ~ meta.rights_copyright_translation;
    }
    if (meta.rights_copyright_illustrations.length > 0) {
      output ~= "  rights.copyright_illustrations: " ~ meta.rights_copyright_illustrations;
    }
    if (meta.rights_copyright_photographs.length > 0) {
      output ~= "  rights.copyright_photographs: " ~ meta.rights_copyright_photographs;
    }
    if (meta.rights_copyright_cover.length > 0) {
      output ~= "  rights.copyright_cover: " ~ meta.rights_copyright_cover;
    }
    if (meta.rights_copyright_audio.length > 0) {
      output ~= "  rights.copyright_audio: " ~ meta.rights_copyright_audio;
    }
    if (meta.rights_copyright_video.length > 0) {
      output ~= "  rights.copyright_video: " ~ meta.rights_copyright_video;
    }
    if (meta.rights_license.length > 0) {
      output ~= "  rights.license: " ~ meta.rights_license;
    }
    if (meta.classify_topic_register.length > 0) {
      output ~= "  classify.topic_register: " ~ meta.classify_topic_register;
    }
    if (meta.classify_subject.length > 0) {
      output ~= "  classify.subject: " ~ meta.classify_subject;
    }
    if (meta.classify_keywords.length > 0) {
      output ~= "  classify.keywords: " ~ meta.classify_keywords;
    }
    if (meta.classify_loc.length > 0) {
      output ~= "  classify.loc: " ~ meta.classify_loc;
    }
    if (meta.classify_dewey.length > 0) {
      output ~= "  classify.dewey: " ~ meta.classify_dewey;
    }
    if (meta.identifier_isbn.length > 0) {
      output ~= "  identifier.isbn: " ~ meta.identifier_isbn;
    }
    if (meta.identifier_oclc.length > 0) {
      output ~= "  identifier.oclc: " ~ meta.identifier_oclc;
    }
    if (meta.language_document.length > 0) {
      output ~= "  language.document: " ~ meta.language_document;
    }
    if (meta.language_document_char.length > 0) {
      output ~= "  language.document_char: " ~ meta.language_document_char;
    }
    if (meta.original_title.length > 0) {
      output ~= "  original.title: " ~ meta.original_title;
    }
    if (meta.original_source.length > 0) {
      output ~= "  original.source: " ~ meta.original_source;
    }
    if (meta.original_language.length > 0) {
      output ~= "  original.language: " ~ meta.original_language;
    }
    if (meta.original_language_char.length > 0) {
      output ~= "  original.language_char: " ~ meta.original_language_char;
    }
    if (meta.notes_abstract.length > 0) {
      output ~= "  notes.abstract: " ~ meta.notes_abstract;
    }
    if (meta.notes_description.length > 0) {
      output ~= "  notes.description: " ~ meta.notes_description;
    }
    if (meta.notes_summary.length > 0) {
      output ~= "  notes.summary: " ~ meta.notes_summary;
    } // check
    output ~= "}";
    output ~= "";
    /+ ↓ @make block +/
    output ~= "@make {";
    auto make = doc_matters.conf_make_meta.make;
    if (make.doc_type.length > 0) {
      output ~= "  doc_type: " ~ make.doc_type;
    }
    if (make.auto_num_top_at_level.length > 0) {
      output ~= "  auto_num_top_at_level: " ~ make.auto_num_top_at_level;
    } // check
    output ~= "  auto_num_top_lv: " ~ make.auto_num_top_lv.to!string;
    output ~= "  auto_num_depth: " ~ make.auto_num_depth.to!string;
    /+ ↓ the make settings the output writers read. the rest of make
         (italics, bold, emphasis, substitute, headings) is read at parse
         time and its effect is already in the objects, so it does not
         travel; these three are read in outputs/io_out/ and must
    +/
    if (make.breaks.length > 0) {
      output ~= "  breaks: " ~ make.breaks;
    }
    if (make.footer.length > 0) {          // a list: joined, each slot escaped
      string[] _ft;
      foreach (_f; make.footer) { _ft ~= sspEscapeValue(_f); }
      output ~= "  footer: " ~ _ft.join("|");
    }
    if (make.home_button_text.length > 0) {
      output ~= "  home_button_text: " ~ make.home_button_text;
    }
    output ~= "}";
    output ~= "";
    /+ ↓ @doc_has block +/
    output ~= "@doc_has {";
    output ~= "  inline_links: " ~ doc_matters.has.inline_links.to!string;
    output ~= "  inline_notes_reg: " ~ doc_matters.has.inline_notes_reg.to!string;
    output ~= "  inline_notes_star: " ~ doc_matters.has.inline_notes_star.to!string;
    output ~= "  tables: " ~ doc_matters.has.tables.to!string;
    output ~= "  codeblocks: " ~ doc_matters.has.codeblocks.to!string;
    output ~= "  images: " ~ doc_matters.has.images.to!string;
    output ~= "  poems: " ~ doc_matters.has.poems.to!string;
    output ~= "  groups: " ~ doc_matters.has.groups.to!string;
    output ~= "  blocks: " ~ doc_matters.has.blocks.to!string;
    output ~= "  quotes: " ~ doc_matters.has.quotes.to!string;
    output ~= "}";
    output ~= "";
    /+ ↓ document sections - every section the abstraction holds, in document order.
         "tail" is the end-of-document used by some output writers
    +/
    string[] section_order = ["head", "toc", "body", "endnotes",
      "glossary", "bibliography", "bookindex", "blurb", "tail"];
    foreach (section; section_order) {
      if (section !in doc_abstraction) { continue; }
      auto section_objs = doc_abstraction[section];
      if (section_objs.length == 0) { continue; }
      output ~= "@" ~ section ~ " {";
      output ~= "";
      foreach (obj; section_objs) {
        output ~= sspObjectRecord(obj, section, doc_matters.opt.action.vox_gt_3);
      }
      output ~= "}";
      output ~= "";
    }
    return output;
  }
  @trusted void spineAbstractionTxt(D)(D doc) {
    auto doc_matters = doc.matters;
    string[] output = sspDocumentLines(doc);
    /+ ↓ write to file, into the pod's own tree:
         pod/<doc>/media/abstraction/<doc_uid_out>.ssp
         .
         where it sits beside pod/<doc>/media/image/, which is what a .ssp
         needs to be a document source: the file describes its images by
         name, size, pixels and digest, and they have to be findable. Written
         here once; --pod2 then digests and zips it where it stands rather
         than copying it in from an output directory of its own.
    +/
    auto pths_pod = spinePathsPods!()(doc_matters);
    string base_pth
      = pths_pod.abstraction_root(doc_matters.src.filename).filesystem_open_zpod.to!string;
    /+ ↓ this directory is the one part of the pod written before the pod is
         built, so the pod builder leaves it alone. It therefore clears itself
         here, or a .ssp for a language the document no longer has would linger
         and be bundled.
         .
         Every language of a document writes into this one directory, and the
         languages may be running at once, so the clearing is done once per
         directory per run, by whichever language reaches it first, with the
         lock held across it. A language that finds the directory already
         prepared passed through this lock before writing, so the clearing it
         skipped had already finished, and no .ssp written by this run can be
         removed by it. Keying the clearing on the manifest's first language
         instead makes it wait for a thread that may be scheduled last, and
         take the .ssp already written by the other languages with it.
    +/
    synchronized {
      if (base_pth !in _abstraction_dir_prepared) {
        _abstraction_dir_prepared[base_pth] = true;
        try {
          if (!exists(base_pth)) {
            base_pth.mkdirRecurse;
          } else {
            foreach (string _f; dirEntries(base_pth, "*.ssp", SpanMode.shallow)) {
              _f.remove;
            }
          }
        } catch (Exception ex) {
        }
      }
    }
    string out_file = ((base_pth.chainPath(
      doc_matters.src.doc_uid_out ~ ".ssp")).asNormalizedPath).array;
    if (doc_matters.opt.action.vox_gt_1) {
      writeln(" ", out_file);
    }
    auto f = File(out_file, "w");
    foreach (line; output) {
      f.writeln(line);
    }
  }
}
#+END_SRC

* org includes
** ocda ssp format version

#+NAME: ocda_ssp_format_version
#+HEADER: :noweb yes
#+BEGIN_SRC emacs-lisp
<<./sisudoc_spine_version_info_and_doc_header_including_copyright_and_license.org:ocda_ssp_format_version()>>
#+END_SRC

#+NAME: ocda_ssp_format_version_part_major
#+HEADER: :noweb yes
#+BEGIN_SRC emacs-lisp
<<./sisudoc_spine_version_info_and_doc_header_including_copyright_and_license.org:ocda_ssp_format_version_part_major()>>
#+END_SRC

** project version

#+NAME: spine_version
#+HEADER: :noweb yes
#+BEGIN_SRC emacs-lisp
<<./sisudoc_spine_version_info_and_doc_header_including_copyright_and_license.org:spine_project_version()>>
#+END_SRC

** year

#+NAME: year
#+HEADER: :noweb yes
#+BEGIN_SRC emacs-lisp
<<./sisudoc_spine_version_info_and_doc_header_including_copyright_and_license.org:year()>>
#+END_SRC

** document header including copyright & license

#+NAME: doc_header_including_copyright_and_license
#+HEADER: :noweb yes
#+BEGIN_SRC emacs-lisp
<<./sisudoc_spine_version_info_and_doc_header_including_copyright_and_license.org:spine_doc_header_including_copyright_and_license()>>
#+END_SRC

* __END__